The inductive transmission of electrical energy is known within the art. A connector for the inductive transmission of energy is a non-galvanic connector. In its simplest form, a connector for the inductive energy transmission consists of a transformer in which a primary side sits in one half of the connector and a secondary side sits in the other half of the connector. A short distance between the primary side and the secondary side gives little loss of energy, whereas the energy loss increases with increasing distance between the primary side and the secondary side. The patent publication WO2005/106902 discloses a device for such an inductive transmission of electrical energy. According to this patent publication, a power source connected to a resonant circuit is frequency-regulated. It is also known that communication signals may be transmitted in the same way.
The inductive transmission of electrical energy is known for charging electric toothbrushes, among other things. The patent publication JP H05236663 discloses a toothbrush with a secondary coil which is positioned in a rounded end portion. The toothbrush is charged by the toothbrush being placed in a holder which supports the toothbrush in such a way that the toothbrush is held in a vertically oriented position. The holder is provided with a spherical recess for the end portion of the toothbrush. A primary coil is positioned underneath the spherical recess. The patent publication CN 202550219 discloses a connector for the inductive transmission of energy and “wireless local area network” (WLAN) data. The connector can be used under water. The connector includes a male part and a complementary female part. The male part is formed as a truncated cone. The patent publication DE 19621003 discloses a plug connector for the inductive transmission of energy and signals. The plug connector includes a male part and a complementary female part. The male part is formed as a cylinder with an end portion formed as a truncated cone. The male part includes a core consisting of sintered ferrite. A primary coil is wound around a portion of the core. The female part includes a sleeve formed out of an injection-moulded plastic-bonded ferrite material. A secondary coil is wound around a portion of the sleeve. The patent publication U.S. Pat. No. 3,743,989 discloses a plug connection for the inductive transmission of energy and signals. The plug connection includes a male part and a complementary female part. The shape of the male part includes a short cylinder and a following long portion which is formed as a truncated cone. The plug connection is suitable for use in sea water. Surfaces that will come into contact with the sea water are covered with a coating that includes neoprene with an added anti-fouling agent. This gives protection against corrosion and fouling.
The inductive transmission of energy and signals is particularly advantageous in sea water as sea water has good electrical conducting properties. In the petroleum industry, it is known to use remote-operated underwater vehicles, so-called ROVs. Further, it is known that ROVs may manipulate connectors for inductive energy transmission under water by moving a male part into a female part or a female part onto a male part.
A drawback of using inductive energy transmission is that it is a limited amount of energy that may be transmitted. The amount of energy that may be transmitted is dependent on the area between the primary side and the secondary side, among other things. A drawback of known connectors for inductive energy transmission that are to be operated by an ROV is that it is difficult for an ROV operator to make the male part hit and connect to the female part, or the female part hit and connect to the male part. ROVs are affected by water currents, and the ROV has an inert mass that may make it difficult to manoeuvre with the precision required.